JPS62186534A - Etching method - Google Patents

Abstract

PURPOSE:To etch a polyimide layer finely without defects, by performing the etching with a metal layer and a silicon oxide layer, which is formed on the metal layer, as masks. CONSTITUTION:On a polyimide layer 2, which is formed on a wafer 1, a metal layer 3 made of aluminum, molibdenum and the like is formed. A very thin photoresist layer 4 is formed between the polyimide layer 2 and the metal layer 3. A silicon oxide layer 5 is formed with spin off glass, and the metal layer 3 is covered. A photoresist layer 6 is formed, and patterning is performed. The silicon oxide layer 5 and the metal layer 3 are patterned. The polyimide layer 2 is etched by a reactive ion etching method. The photoresist layer 6 is usually removed during the etching of the polyimide. The silicon oxide layer 5 and the metal layer 3 are removed by the lift-off method of the photoresist 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for etching polyimide 11, and particularly to the improvement of a mask.

[Summary of the invention]

In the method of etching a polyimide layer, by forming the entire silicon oxide layer on the metal layer and stacking it on the metal layer,
This completely prevents the generation of protruding residues during etching, and since there is a metal layer under the silicon oxide layer, it can be used as a mask by relieving defects.

[Conventional technology]

The conventional polyimide layer etching method uses a mask as a mask when selectively etching the entire polyimide layer on a wafer.
Photoresist, metals such as aluminum or molybdenum, or spin-on glass are used.

[Problem that the invention seeks to solve]

However, in the prior art described above, in the case of photoresist,
In ion etching using a gas mainly composed of oxygen, the etching rate of the photoresist is 1.5 times or more than the etching rate of polyimide, resulting in a thick photoresist).
Since it is necessary to form II, fine processing is difficult. In the case of metals such as aluminum and molybdenum, protruding residues that are very difficult to remove are likely to occur during etching, and in the case of spin-on glass, mask defects due to pinholes in the film are likely to occur. The present invention solves these problems, and its purpose is to provide a mask material with fewer defects that can be used as a mask during ion etching of polyimide layers, which can be used as a mask during ion etching of polyimide layers. It is in.

[Means to solve all problems]

In the etching method of the present invention, polyimide rt is etched as a mask over a metal layer and a silicon oxide layer formed on the metal layer.
It is characterized by etching.

〔Example〕

The following two aspects of the present invention will be described based on examples.

FIG. 1 is a diagram showing an example of the present invention in order of steps. First, as shown in figure a, polyimide layer 2 is formed on Ueno-1.
1% of metals such as aluminum and molybdenum on top 3 'e
Form a shadow. If an extremely thin photoresist (#4') is formed between the polyimide layer and the metal layer, it can be peeled off at each location by a full mask material lift-off method in a post-process.

Next, as shown in figure b, a silicon oxide layer 5 is formed by spin-on glass, and gold J! The T4 layer 3 is completely removed to prevent the generation of protruding residues during etching.

Furthermore, due to the presence of the metal layer in the pinholes of the silicon oxide layer 5, it is transferred to the L9 polyimide f-.

Next, as shown in FIG. 0, seven photoresist edges 6 are formed and patterned. Photoregis! - #6 When the etching of U polyimide is completed, there is no need to leave 1 on, so it is possible to form a fine a pattern because the light beam is thin.

Next, as shown in figure d, a silicon oxide layer 5 and a metal 1-
3. Buttering.

As shown in the following Ke diagram, the polyimide layer 2 is etched using a reactive ion etching method using a gas mainly composed of oxygen or YR. Photoresist number 6 is typically removed during the polyimide etch.

Next, as shown in Figure F, the silicon oxide layer 5 and the metal ml are removed by a lift-off method of the photoresist 4, thereby completing the etching process.

〔Effect of the invention〕

As described above, according to the etching method of the present invention, a polyimide layer can be etched finely and with few defects.

[Brief explanation of drawings]

FIG. 1 (- to (f) U is a process diagram of an embodiment of the etching method of the present invention. 1...--Item wafer 2... Polyimide layer 6... Metal layer 4...Photoresist)/It 5...Silicon oxide layer 6...Photoresist layer or above

Claims (1)

[Claims] (1) A polyimide layer etching method characterized by etching using a metal layer and a silicon oxide layer formed on the metal layer as a mask.